1. Cochrane South Africa, South African Medical Research Council, Cape Town, South Africa
2. School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
3. Division of Epidemiology and Biostatistics, Department of Global Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
4. Division of Epidemiology and Biostatistics, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa